1. Field of the Invention
The present invention generally relates to a document feeder for a facsimile machine, for example. More particularly, it relates to a document feeder for a facsimile machine which can feed a document into the facsimile machine without drawing it to the right or left.
2. Description of the Related Art
Office automation machines such as facsimile machines, photocopiers, printers, etc. are pervasive in the industrialized world, greatly improving efficiency. Since the use of these devices in homes as well as offices is increasing, manufacturers have been developing low-priced office automation machines equipped with various functions to meet the demand of buyers. Two objectives of current research and development is the development of machines which save space and lower production costs.
In line with this trend, a presently-available facsimile machine is designed to operate with just two or three rollers. The reading roller also serves as a compression roller, a write roller, and a paper output roller, and is used for the low-priced systems. A document to be sent is moved by a document feed roller and pressed against a reading glass so that the document is scanned by a document reading section. When a cylindrical reading roller rotates, the document is conveyed to the facsimile printing head. At this point, the right and left sides of the reading roller equally contact the document reading section.
When the reading roller is made of rubber and its outer circumference is not even throughout the length of the roller, the document is drawn toward the larger end of the reading roller, causing the document to be off-centered. For example, when the circumference at a contact area, towards the left end of reading roller in contact with the document reading section, is larger the circumference of the roller towards the right end the document moves to the left. If the contact area towards the right has a larger circumference than the left end of the roller where the reading roller contacts the document reading section, the document moves to the right.
The following patents each disclose feature of the present invention but do not teach or suggest the specifically recited document feeder of the present invention in which an elastic means is mounted at the center of the document reading section in accordance with the present invention.
U.S. Pat. No. 4,953,037 to Ito et al, entitled Original Reading Apparatus, U.S. Pat. No. 5,077,618 to Sakai et al., entitled Image Data Processing Apparatus, U.S. Pat. No. 5,267,058 to Sata, entitled Original Feeding And Reading Apparatus In Which The Original Is Pressed Against The Image Sensor, U.S. Pat. No. 5,278,677 to Lee et al., entitled Device For Removing Document Jamming Generated At A Transmitter Of A Facsimile Using A Contact Image Sensor, U.S. Pat. No. 5,379,121 to Yamada et al., entitled Portable Facsimile Apparatus, U.S. Pat. No. 5,448,374 to Yokoyama et al., entitled Facsimile Apparatus And Roll-Like Sheet Holder, U.S. Pat. No. 5,504,586 to Garcia et al., entitled Method And Device For Placing Of drive Counter-Rolls Under Pressure In A Machine Such As A Facsimile Machine, U.S. Pat. No. 5,510,909 to Morikawa et al., entitled Image Reading Apparatus Having A Paper Guide Mechanism With Spring Biased Locking Releasing Pieces Connected By Symmetrical Movement And Locking Mechanisms, U.S. Pat. No. 5,517,332 to Barry et al., entitled Document Scanner Having One-Piece Housing For Holding An Image Sensor, Drive Roller And Document Sensors In Close Alignment With Each Other, and U.S. Pat. No. 5,519,512 to Bandai et al., entitled Facsimile Apparatus Having Reduced Profile.